Conventional wisdom in the United States in managing patients with newly-diagnosed open angle glaucoma is to institute topical medical therapy. The medical regimen is increased as necessary to achieve an intraocular pressure reduction considered sufficient to preclude progression of optic nerve and visual field damage. If the medical regimen is inadequate, argon laser trabeculoplasty is often tried if there is a reasonable expectation that adequate pressure reduction might be achieved. If such an expectation is not realistic and/or if argon laser trabeculoplasty is tried and fails to control intraocular pressure, incisional filtration surgery is utilized. Recent studies, particularly in Great Britain, suggest that initial treatment for open angle glaucoma is best handled with filtration surgery and that the rationale for such an approach is based on better outcomes of visual function parameters. The proposed clinical trial will randomize patients with newly-diagnosed open angle glaucoma to either a medical regimen or a surgical approach. Assessments will be made of visual function, intraocular pressure, and the quality of life achieved by patients on the medical and surgical regimens. Null hypotheses to be tested include the lack of a difference between the two treatment modalities in terms of preservation of visual function, level of intraocular pressure achieved, and overall life satisfaction experienced. This clinical trial will take place at 11 Clinical Centers and will include the participation of community ophthal- mologists to not only assist in recruitment and management of patients, but to improve the generalizability of the trial's results.